1. Field of the Inventions
The present inventions relate to a small planing boat with an intercooler for cooling air used by the engine for combustion.
2. Description of the Related Art
Small planing boats, including those commonly referred to as “personal watercraft”, generate propulsion forces by drawing in water from a water inlet on the bottom of their hull and discharge it rearwardly with a jet pump. Recently, personal watercraft with turbo chargers and super chargers have become commercially available. In certain of these watercraft, both a compressor, such as a turbo or a supercharger are used to compress air to be supplied to the engine, which raises the temperature. Additionally, Certain of these watercraft include an intercooler to cool the compressed air, and thereby increase the density of the compressed air, thereby improving the engine output and in particular acceleration properties. For example, U.S. Pat. No. 6,746,288 discloses such a watercraft.
In this type of small planing boat, the engine can be disposed with its crankshaft extending in the longitudinal direction of the body and a compressor (in this case a turbocharger) can be disposed toward the rear of the engine. An intake manifold can be disposed at an upper part of the side of the engine and an intercooler can be disposed, extending longitudinally, at the side of the engine below the intake manifold. The compressor and the upper rearward portion of the intercooler are connected by a pipe and the upper forward portion of the intercooler and the intake manifold are connected by a tube.
Inside the intercooler is a cooling unit. On both longitudinal ends of the cooling unit are connected cooling hoses protruding from approximately the middle of the intercooler between its longitudinal ends. Cooling water enters the cooling unit from the center of the intercooler at the forward end and exits from the center of the intercooler at the rear end after cooling air in the intercooler by heat exchange while passing through the cooling unit. Therefore, air compressed by the compressor is cooled by the intercooler and the cooled, compressed air is supplied to cylinders of the engine through the intake manifold.